"Gazelle" Gas-2705>> Brake system>> Maintenance service and repair of brake systems>> Repair of the brake mechanism of a forward wheel
Dismantling of the case brake скобы is made at replacement of pistons, fingers, sealing rubber details.
For case dismantling it is necessary:
- To disconnect a flexible hose from the case brake скобы;
- To remove brake колодки;
- To take brake колодки and to mark them that at the subsequent assemblage to put on a former place;
- To remove a cover of a finger from the basis;
- To take the case with a finger from a basis aperture;

Fig. 8.13. Case dismantling скобы




- To establish between the piston and the case wooden брусок in the thickness of 20-25 mm (fig. 8.13);
- To push out the piston from the cylinder, having connected a hose with low pressure of air to an inlet aperture of the case;
- To remove a cover of the piston from a flute of the piston and to take the piston from the case, and a cover from a case flute;
- To take the dulled shovel a sealing ring from the case.
Having executed these operations, to wash out all details изопропиловым spirit or a fresh brake liquid.


The prevention
Is inadmissible to use for washing gasoline, solvents or other liquids on a mineral basis

To check up all details on presence of deterioration, damages and corrosion, paying special attention on working surfaces of the piston and a cylinder aperture. Edges of a sealing ring should be sharp, without закруглений, and surfaces equal, without вырывов. In the presence of strong corrosion on a working surface of the piston it is necessary to replace it.
Assemblage of the case brake скобы.
After check and replacement of the failed details to collect the case brake скобы taking into account following recommendations:
- Before assemblage to be convinced that working and sealing surfaces of the case pure; to grease with liquid НГ-213 THAT 38.10.1129-80 sealing ring and to establish it in a case flute;

Fig. 8.14. Assemblage of the case brake скобы




- To grease with liquid НГ-213 a working surface of the piston and a cover and to establish last on the piston (fig. 8.14). Without displacing from the end of the piston a cover, to fill it in a case flute;
- Cautiously hand to insert the piston with a cover into a case aperture. To fill a cover in a piston flute;
- To establish the case with fingers in basis apertures;
- To establish колодки on a former place;
- To connect a flexible hose to the case скобы.
Replacement of directing fingers is necessary for making in a following order:
- To execute operations on removal brake колодок. Thus it is necessary to mark колодки that at subsequent assemblage to establish them on a former place;

Fig. 8.15. Replacement of directing fingers




- To turn out a bolt of fastening of the second directing finger (fig. 8.15);
- To remove covers of fingers from the basis;
- To take directing fingers from basis apertures;
- To replace the worn out directing fingers, preliminary having greased with their greasing УНИТОЛ-1 and having put on them protective covers (covers should not have damages);
- To execute done before operation in return sequence.
Basis replacement.
For basis replacement it is necessary:
- To disconnect the case from the basis (see above);
— To take brake колодки from the basis and to mark them that at the subsequent assemblage to put on a former place;
- To turn out two bolts of fastening of the basis to a rotary fist and to remove the basis;
- To establish the new basis on a rotary fist and to wrap bolts of fastening of the basis the moment 100 125 Н·м (10—12,5 кгс·м), preliminary having cleared carving surfaces of a fist and bolts of old hermetic and to put on bolts fresh hermetic "Unigerm-6" THAT 6-01-1285-84.
The further assemblage to make (Assemblage of the case brake скобы ») see«.
Repair of a brake disk.
The disk is exposed to repair if its working surfaces have deep risks and axial palpation more than 0,1 mm. Axial palpation of working surfaces of a disk is checked by the indicator at disk rotation on nave bearings.
For disk repair it is necessary:
- To remove the case and the basis from a rotary fist («basis Replacement» see);
- To remove a disk from a nave for what to turn away bolts with spring washers;
- прошлифовать working surfaces of a disk on the basis of its face surface adjoining to a nave.
At polishing it is necessary to provide the minimum difference on processing between disk walls. The size of the total admission of parallelism and planeness of a working surface of a disk concerning a base surface should be no more than 0,05 mm (that corresponds to a difference in the indicator indication at its moving on a checked surface), and the size of the total admission of parallelism of working surfaces of a disk among themselves should be not less than 0,03 mm. The thickness of a disk after repolishing should be not less than 19 mm, and the roughness of its working surfaces should be no more than 1,25 microns in accordance with GOST 2789-73.
At detection of cracks or deep рисок, and also at a thickness of a disk less than 19 mm are necessary to replace a disk new.
For this purpose it is necessary to establish a disk on a nave and to wrap bolts of fastening of a disk the moment 44—56 Н·м (4,4—5,6 кгс·м). To establish the case brake скобы on a rotary fist («basis Replacement» and «Replacement колодок brake mechanisms of forward wheels» see).




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